• Journal of Fisheries and Marine Sciences Education
• /
• v.29 no.3
• /
• pp.888-898
• /
• 2017

Tenebrio molitor larvae, also known as yellow mealworms (MW), are rich in protein and lipid and can serve as a potential alternative protein and energy source in commercial aquafeeds. Therefore, this study attempts to evaluate the effects of different drying methods on the nutritional value of MW meal. For this, live MW were cold-anaesthetized before being subjected to three different types of drying methods, including freeze-drying, oven-drying at $60^{\circ}C$ and air-drying at room temperature for three days, and compared for proximate composition and energy content. An in-vivo digestibility test was then conducted to evaluate the nutrient digestibility of MW meal in diets for rockfish, Sebastes schlegeli. A test diet was prepared by mixing the MW meal with a reference diet (Ref) in a 30:70 ratio with chromium oxide as an inert marker at the inclusion level of 0.5%. Rockfish with mean body weight of 150 g were stocked into a fecal collection system equipped with fiberglass tanks of 400 L capacity. Each group of fish was fed one of the experimental diets to apparent satiation for 4 weeks. The results of the proximate analysis showed that drying methods had no significant effect on crude protein, crude lipid, ash and energy contents of MW. Despite being a rich source of protein and lipid, MW meal was deficient in certain amino acids, particularly methionine, and highly unsaturated fatty acids, particularly 22:6n-3 (DHA) and 20:5n-3 (EPA). MW meal showed high digestibility values for protein (93%), lipid (97%) and energy (88%). These results may indicate that MW meal is a nutritious and acceptable feed ingredient, with comparable digestibility values to conventional animal and plant feedstuffs such as fish meal and soybean meal, in practical diet for rockfish at grower stage.

• Fisheries and Aquatic Sciences
• /
• v.24 no.3
• /
• pp.109-120
• /
• 2021

Protein hydrolysates and krill meal (KM) are used as protein sources in aquafeeds. The study was conducted to examine the supplemental effects of shrimp protein hydrolysates (SH) or KM in a high-plant-protein diet for red seabream (Pagrus major). A fish meal (FM)-based diet (40%) was considered as the high-FM diet (HFM) and a diet containing 25% FM and soy protein concentrate, in the expense of FM protein from HFM diet, was considered as the low fish meal (LFM) diet. Two other experimental diets (SH and KM) were prepared by including SH and KM into LFM diet at 5% inclusion levels in exchange of 5% FM from the LFM diet. A feeding trial was conducted for fifteen weeks using triplicate group of fish (Initial mean body weight, 8.47 ± 0.05 g) for a diet. Growth performance and feed efficiency of fish were significantly enhanced by HFM, KM and SH supplemented diets over those of fish fed LFM diet. Interestingly, these parameters of fish fed SH diet showed better performance than KM and HFM groups. Liver IGF-I expression of fish fed SH diet was comparable to HFM group and higher than KM and LFM diets. Protein digestibility of SH diet was significantly higher than KM, HFM, and LFM diets. Dry matter digestibility of SH diet was comparable to HFM diet and significantly higher than KM and LFM diets. Nitro blue tetrazolium and superoxide dismutase activities of HFM, SH and KM groups were significantly elevated than the LFM group and SH diet increased catalase and glutathione peroxidase activities of fish compared to KM and LFM groups. Hemoglobin level and hematocrit of fish fed SH and KM diets were significantly higher than LFM group. A diet containing 20% FM with KM is comparable to a HFM diet which contains 40% FM for red seabream. SH can be used to replace FM from red seabream diet down to 20% and fish performance can be improved better than a diet containing 40% FM. Overall, it seems that SH is more effective ingredient in red seabream diet compared to KM.

• Fisheries and Aquatic Sciences
• /
• v.26 no.12
• /
• pp.726-737
• /
• 2023

Piperine, the main bioactive component of black pepper (Piper nigrum Linn.), has anti-inflammatory, antifungal, and antibacterial properties. This study evaluated the supplemental effects of piperine or black pepper on innate immunity, growth, feed utilization efficiency, and intestinal morphology in red seabream (Pagrus major). Six experimental diets were formulated, supplementing piperine at 0.0, 0.25, 0.5, 1.0, and 2.0 g/kg levels (Con, P25, P50, P100, and P200) or 1.0 g/kg black pepper (BP100). Juvenile fish (7.6 ± 0.1 g) were randomly stocked into 18 circular tanks (220 L), including 30 fish per tank. Each diet was randomly assigned to triplicate groups, and the feeding trial was conducted for 8 weeks. The results showed that final body weight, specific growth rate, weight gain, and feed utilization efficiency were significantly improved (p < 0.05) when piperine was supplemented into diets at 0.25-2.0 g/kg levels compared to the Con group. Compared to the Con diet, condition factor was significantly increased (p < 0.05) in fish fed with dietary piperine at 0.25-2.0 g/kg or BP100 diet. Serum myeloperoxidase activity was increased (p < 0.05) in P25 and P100 groups and antiprotease activity was increased (p < 0.05) in P100 group compared to the Con group. Significantly higher (p < 0.05) lysozyme activity was observed in P50, P100, P200 and BP100 groups, while total immunoglobulin level was increased in P50, P100 and BP100 groups than Con group. Superoxide dismutase activity was increased (p < 0.05) by dietary piperine at 0.25-2.0 g/kg levels and BP100 diet compared to Con diet. Plasma cholesterol was significantly lower (p < 0.05) in fish fed with piperine (0.5-2.0 g/kg) or BP100 compared to the Con diet. Compared to the Con diet significantly longer (p < 0.05) intestinal villi were observed in fish fed with piperine at 0.25-1.0 g/kg levels, and higher goblet cell count was observed in P25 and BP100 groups. Dietary inclusion of piperine would be a potent immunostimulant in fish diet and the optimum supplementation level would be 0.25-1.0 g/kg.